JPS61102742A - Method of filling groove for separation of dielectric - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for filling deep dielectric isolation trenches in semiconductor devices.

B. SUMMARY OF THE DISCLOSURE
Deep dielectric isolation trenches in semiconductor devices are filled by a method using filtered solutions of atic acid.

C1 To obtain improved semiconductor devices with higher density and higher speed than the prior art, there is a need to use deep dielectric isolation trenches. Such grooves can be filled with polyimide resin or poly/rif/. Regarding this, for example, Japan Institute of Invention and Innovation Technical Publication No. 1658-138049,
46 pages, and ■8M Technical Disclosure Bulletin, Volume 25, No. 12, May 1983,
It is described in the literature on pages 6611 to 6614.

U.S. Pat. No. 4,539,526 shows the use of branched polyphenylene prepolymers with acetylene end groups as protective coatings for integrated circuit devices. However, that Specification H does not discuss filling deep dielectric isolation trenches and does not disclose the method of the present invention.

D6 Problems to be Solved by the Invention Grooves for separating the itt bodies (width of about 1 to 2 microns and
In the development of semiconductor devices using micron depths, many problems have arisen when using polyimide or polysilicon. Polyimide used in the prior art does not completely fill the grooves. Furthermore, these polyimides absorb solvents, water and gases, significantly complicating their processing. Polyimides are only soluble in a limited number of solvents and usually require adhesion promoters.

Their curing is accompanied by the evolution of volatile products. Cured polyimide swells in many processing solvents? However, there are limits to their flattening. Polynolycone, which is also used in the prior art, has the disadvantages of requiring very expensive vapor deposition processes, creating localized stresses, and not being a very good electrical insulator. The materials used in the method of the present invention overcome all those drawbacks of the prior art.

E9 Means for Solving Problems The method of the present invention is a method for filling deep dielectric isolation trenches in semiconductor devices; Dissolve in 2 to 2
forming a solution having a viscosity of 000 cs; filtering the solution; coating a semiconductor device containing the groove with the solution;
A method of filling a trench for dielectric isolation is provided, comprising: forming a coating; evaporating the solvent; and heating and curing the coating.

In the process structure of the present invention, an aromatic polymer oligomer having reactive ethynyl groups is first dissolved in a solvent to form a solution having a controlled viscosity.

The solution is then filtered through a very fine filter and the semiconductor device containing the grooves is coated with the solution to form a coating. When the semiconductor element is heated, the solvent evaporates and the coating is oxidized. The solvent has evaporated, but before the coating is cured, the oligomer melts and flows in the a-degree range from ambient conditions to about 160°C, particularly at 80 to 125°C, and flows through the grooves. Fill. The oligomer is then polymerized by reaction of the ethynyl groups at higher temperatures.

The method of the present invention uses an aromatic electropolymer oligomer having reactive ethynyl groups as the material filling the grooves. These materials are known in the art and include triethynylbenzene (TEB), jetynyl diphenyl ether (
Derived from a number of different monomers, including DEDPE), and phenylacetylene (PA). Other useful aromatic acetylene-containing monomers include, for example, U.S. Pat.
No. 97460.

One advantage of the method of the invention is that it can be used with any number of solvents. Initially: τ, the oligomer is dissolved in a solvent and deposited onto the semiconductor device by spin coating. Useful solvents include, for example, N-methylpyrrolidinone, quinolene, dichromate, mesitylene, diethylbenzene, propylene glycol monomethyl ether acetate, tetraglyme, isophorone, peratol, m-dimethynebenzene, Examples include butyrolactone, toluene, chloroform, dioxane, dichloromethane, etc.

During the coating process, the viscosity of the solution should be adjusted so that the grooves are completely filled. Its viscosity is adjusted in two ways. In one method, the ratio of solvent to solute is adjusted; the more dilute the solution, the lower its viscosity. On the other hand, the molecular weight of the oligomer is adjusted; the smaller ,j-;l is, the lower its viscosity will be.

Generally, it is preferred that the solution has a viscosity of about 2 to 300 C9 viscosity. If the viscosity is higher than about 2000 cs, complete filling will not occur, especially at the corners of the grooves. When the viscosity is lower than about 2c3, uniform and intimate groove filling is difficult to achieve.

It is important to filter and strain the oligomer solution before carrying out the coating treatment. Even a small amount of turbid particles can cause serious contamination of semiconductor devices. Such filtration is easily accomplished using, for example, a 0.5 micron filter.

Evaporation of the solvent is easily accomplished by simple heating, and curing of the coating is likewise accomplished by heating.

With the method of the invention, significantly better results were obtained in completely filling the grooves. The filling material is thermally stable up to 400°C without any decomposition or evolution of volatile substances.

F, Examples Example 1 Monomer jetinyl diphenyl ether (DBDP
E) (825 mmo4) was placed in a 16 4 neck round bottom flask. Next, nickel-2°4-penta/dionate (4,16 mmot) and triphenylphosphine (11,6 mmot) were added and washed in phenylacetylene (1320 mmot) and dioxane (301 mmot). The flask was equipped with a matching pair of reflux condensers, nitrogen and vacuum inlets and vacuum regulators, an overhead stirrer, a heating mantle, and a thermocouple. The contents were stirred under nitrogen until the reaction was homogeneous. Oxygen was then removed from the flask six times using vacuum and nitrogen. The surface temperature of the mantle is 200℃
and keep the temperature inside the flask at 90℃ for 6 and a half hours.
A vacuum regulator was used to control reflux at that temperature (15-18 Hr).

At this point, the reaction was cooled to reflux under vacuum.

The thick polymer solution mentioned above? , diluted with dioxane with a small amount of ammonium hydroxide and methanol, and stirred to apply large shear rate changes, 6 times the volume 10:1.
of methanol and ammonium hydroxide. The precipitated polymer was separated by filtration, washed with methanol and dried under vacuum. The nickel content of the above polymer was further reduced by extraction with acid.
6 of Toluev, 5% aqueous HC4 solution (3x3
00ml) and water (2X500mt), dried over My SO4 and filtered once more.

The resulting polymer solution was precipitated by slowly adding it to 5 times the volume of rapidly stirring methanol, the polymer was separated by filtration, washed with methanol and
Poly(ethynyl phenyl ether) (PEPE) of 248F was obtained with dry eL in a vacuum oven at 0°C.

40% by weight dissolved in 1.3-dimethoxy/benzene
A solution of PEPE was formed. The solution was mixed with 05 μF
luoropore (Millipore)
eCorp, Inc.) filter and then deposited onto a groove-containing silicone urchin.

The wafer was spun at 4000 rpm for 60 seconds and placed on an 80° C. hot plate under nitrogen.

The hot plate was heated to 425°C and maintained at that temperature for 60 minutes. Then, the hot plate was cooled to room temperature and the ueno was taken out. As a result of the above method, sea urchins with excellent surface flatness, without any unfilled voids, were obtained from a 5μ PEPE coating.

Example 2 A 4-neck round bottom flask containing 1 was prepared equipped with a heating mantle, an overhead stirrer, a powder funnel, and two compatible reflux condensers with nitrogen and vacuum inlets, respectively. The inlet was connected via a manifold to the pulp which was connected to a nitrogen and vacuum system. The device should have a vacuum regulator. While introducing 9 elements through the above device, 7
8.20? (0,50mot, 1.50 no
/, ethynyl group) of triethynylbenzene (TEB,
96%), 110.225' (0,50mot, 1.
00mot ethynyl group) jetynyl diphenyl ether (DEDPE.

99chi), 1.83? (6,2'5 mmot) of nickel-2,4-pentanedionate dihydrate, and 4
It was charged with 60P (175 mmot) of triphenylphosphine. 222ml (2,02mot) of the above powder
of phenylacetylene (PA) and the PA was washed in 368 ml of dioxa/PA. At that time, the amount of the reaction system was 50% by weight in the monomer.

The powder funnel was replaced with a thermowell and the reaction was stirred until it was homogeneous.

After removing oxygen from the reaction mixture six times using
5 minutes). To control the reflux at 75°C,
A vacuum was applied at 70-75°C.

When the desired molecular weight range was reached, the reaction system was cooled to room temperature by reflux. Dioxane was removed under vacuum. The residue was redissolved in 500 mt of methylene chloride. The organic solution was dissolved in 5% aqueous HCt solution (3X 200 ml
) and deionized water (2 x 200 ml). The organic phase was dried over magnes/sor and passed through 1002 silica gel. The solution was allowed to evaporate until the total weight was 8002. 2
Add 02 diatomaceous earth and 202 magne/rum sulfate,
Filtered again.

The prepolymer was precipitated by dropping the above solution into rapidly stirring 107 methanol. The golden mass was filtered through a coarse glass fritted funnel, and the filter mass was washed with 250 mt of methanol and briefly dried. The polymer was dried overnight in a vacuum oven at 45-55°C. Expected yields vary depending on reaction time. In the case of a 20 minute reaction, the yield was 113.11P (29
A polymer with an M of 2100 was obtained.

The above polymer, namely single stave acetylenic thermoset prepolymer (SSATP), was analyzed by NMR.
As a result of analysis using toluene as an internal standard, the content of terminal acetylene was determined to be 912 mmot/f. The above 5SATP (50, C1, 45
6mmot) and phenylacetylene (1824mmot)
t) into a 500 mt dropping funnel to dissolve the above polymer.

Cuprous chloride (43.8 mmot) and tetramethylethylenediamine (43.8 mmot) were placed in a 3-neck round bottom flask containing 2 and washed in 400 mt of chloroform. The flask was equipped with a magnetic stirrer, a thermocouple, an oxygen aspirator tube, and an addition funnel topped with a dry ice condenser. Stir the catalyst solution and insert the aspirator tube in 1. Oxygen was introduced at 〒. The surface temperature of the mantle was set at 30°C, and the solution was heated to 28°C. The above polymer solution was added quickly.

A slow exotherm increased the reaction temperature to 38°C over 30 minutes. The reaction was maintained at 28°C overnight.

The above reaction mixture was placed in a 21 separatory funnel.

The above polymer solution was mixed with 10% HC4 aqueous M (3X400mt
) and deionized water (2×400 mt).

The solution was dried over magnesium sulfate, filtered and evaporated to dryness by rotation. The polymer was again dissolved in methylene chloride and passed through a 25C1 silica gel column eluting with the methylene chloride. Next, the polymer solution was evaporated to 5002 by rotation,
102 each of magnesium sulfate and diatomaceous earth were added. After stirring the polymer solution, it is rapidly stirred.
It was slowly precipitated into t methanol. Filter the slurry, wash the filter cake with 500 ml of methanol,
After drying in a vacuum oven at 40° C., a 64262 bis-acetylene terminated 7/glu step acetylenic thermoset polymer (BAT-8SATP) was obtained.

40% BA dissolved in N-methylpyrrolidone
A solution of T-8SATP was formed. Add the above solution to 05μ
After filtration through a Fluoropore filter, the wafer containing the grooves/recontamination film attached on top was spun at 4000 rpm for 40 seconds and incubated under nitrogen for 80 minutes.
Place it on a hot plate at ℃. After 60 minutes, heat the hot plate to 100°C and keep it at that temperature for 5 minutes.
It was maintained for 0 minutes. The stepwise heat/maintenance cycle was repeated at 125, 200, 500 and 425°C.

The hot plate was cooled to 400°C and maintained at that temperature for 4 hours. Then, the hot plate was cooled to room temperature and the sea urchins were taken out.

As a result of the above method, a 1 micron coating of BAT-3SATP resulted in a Ueno film with excellent surface flatness and no unfilled voids.

Example 6 The polymer PEPE obtained in the above practical example 1 was subjected to NMR
As a result of analysis using toluene as an internal standard, the content of terminal acetylene was 104 mmot,/r
It was determined that In a 16-pack round bottom flask equipped with a heating mantle, electrical current condenser, nitrogen and vacuum inlets, overhead stirrer, and thermowell.
10 of the above polymer, 2.4 mt of iodobenzene (2
1,6 mmol), 540 mr triphenylphosphine (0,21 mmot), 410 mr copper acetate 0-hydrate (0,21 mmot), 570 m9 palladium chloride (
0.21 mmot), 6.6 mt y-butylamine (
62 mmot) and 100 mj of THF were added. The contents were stirred and deoxygenated three times with nitrogen and the flask was brought to reflux overnight. After the polymer solution was cooled to room temperature, the solvent was removed by evaporation by rotation.
Redissolved in 0 ml chloroform and 10% HC4
Aqueous solution (3X 40 ml) and deionized water (2x5
0rnt). The solution was dried over magnesium sulfate and precipitated into 3t of methanol. The polymer slurry was filtered, washed with methanol, and dried in a vacuum oven at 83? polymer (tran-PEPE)
was gotten.

The ToIan-PEPE described above was also formed by directly reacting tolan capped monomers. Iodobenzene was reacted with f) EDPE and the tolan-capped diethynylnophenyl ether was formed by partial separation of the monomers. The partially capped DEDPE and phenylacetylene were trimerized until no further reaction was observed by infrared techniques. The above process resulted in a polymer similar to PEPE with a tra/reactive position and very little terminal acetylene.

Example 4 Monomer Synthesis 10 equipped with mechanical stirrer, cooler, and nitrogen inlet
In a 3-necked round bottom flask containing 00 ml, add 4°4'-'
; Ethynyldiphenyl ether (DEDPE) C684
y, 300 mmot), triethylamine (ilOml
), and iodobenzene (30,6?, 100mmot
) was added. The mechanically stirred suspension is warmed in a hot water bath until a homogeneous solution is obtained, and the solution is deoxygenated six times using a stream of 9 atoms as the solution is allowed to cool to room temperature. Ta. Next, the catalyst was prepared using bis(triphenylphosphine)palladium dichloride (52m5', 0.5m).
07mmot) and Hitris (triphenylphosphine)
M(I) Chloride (7:l) mP, Q, 07 mm
o! ) was added and the resulting mildly exothermic reaction was tempered using a water bath. After the white slurry was mechanically stirred for 2 hours, more catalyst (same amount as the initial amount) was added and the reaction continued for an additional 6 hours. After this, the flask was fitted with a short-path distillation head, excess triethylamine was removed while warming under vacuum, methanol (200 mt) was added to the resulting solid residue, and the solid was dispersed by stirring.

Add water (200 mt) to the vigorously stirred suspension.
was added over 5 minutes, and 10% HC4 aqueous solution (300 m
t) was added over a period of 10 minutes. After the addition of the HC1 aqueous solution was completed, the slurry was stirred for another 10 minutes and then filtered through a suction filter, and the resulting white solid was mixed with 10% HC6 aqueous solution (200 ml) and water (400 ml).
mt). Air dry the above solid on the filter overnight, then add warmed inooctane (500 ml)
was used to transfer the mixture to a 200 Omt Erlenomayer O flask. Boil the resulting slurry and add silica gel (
20y) and Magnesium/Lum sulphate were added and the hot solution was filtered by gravity through a pad of silica gel and washed with another portion of hot inooctane (300ml). The resulting filtrate was concentrated by rotary evaporation until a cream colored solid (60.0?) was obtained. The above solid is NMR
And as a result of analysis using reversed phase chromatography, 55:
45 (mol'l) of 4-ethynylphenyl-47-phenylnithynylphenyl ether and U 4 , 4'-
It turned out to be a mixture of jetynyl diphenyl ether.

Synthesis of Polymers 102 The above-mentioned tolan-camped monoj1 (thermocomposite (analyzed to be 45 H DEDPE and 55% mono-toran capped DEDPE)
2:1 DEDPE mixed with 3662 DEDPE
and Tolan-DEDPE (37,4 mmot: 18.
A mixture of 7 mmot) was formed. 100 mt with heating mantle, overhead stirrer, thermowell, reflux condenser, nitrogen and vacuum inlets, and vacuum regulator
Phenylacetylene' (2,0
5mt.

18.7 mmot), nickel acetylacetoner)
(310m9, 0.105mmot)
, Triphenylphosphine (75m?,
0.28 mmot) and 15 mt of dioxane were added. The reaction was monitored until no ethynyl was observed by infrared spectroscopy. The above reaction was carried out at 90° C. for 7 hours until no further reaction occurred. 50% of the above reaction system
ml dioxane and precipitated directly into 1400 mt methanol. The slurry was filtered and dried in a vacuum oven overnight to yield 13.0 El (84% yield) of 17
000aM was obtained.

Example 5 Formation of a 'thermal polymer' from DEDPE (4,4'-jethynyldiphenyl ether) and PA (phenylacetylene) Reflux condenser, nine element inlet, mechanical stirrer, and internal thermocouple DEDPE (160!P), PA (732), and diglyme (240F) were placed in a 1000 ml comb 3-neck round bottom flask equipped with a 1000 ml comb 3-neck round bottom flask.

The resulting solution was stirred and heated, and aliquots were removed from the solution from time to time and their viscosity was measured at room temperature. The solution was maintained at reflux (~162°C) for 120 minutes, then gradually cooled to 151°C over the next 90 minutes, and then heated to 52°C.
The temperature was maintained for an additional 70 minutes until the desired viscosity of C3 was obtained. Then simply allow the solution to cool down to room temperature: τ to stop the polymerization and rapidly dissolve the diglyme solution:
The above material was precipitated by addition dropwise into stirred 10x ethanol. A yield of 1072 (~65% of theory) was obtained after collecting the solid by filtration and drying in a stream of nitrogen.

Example 6 ``Groove Filling Process Using Thermopolymer Pa'' The dried Thermopolymer obtained according to Example 5 above was used to obtain a viscosity of 311 cs and 812500, Mw.
A 30 weight solution dissolved in N-methylpyrrolidone was formed with a GPC molecular weight profile of 251,000 and M, 1,390,000. The above N-methylpyrrolidone solution was filtered through a 0.5μ filter onto a groove-containing substrate and spun at 4000 rpm for 40 seconds to form a 20μ film.

The resulting coating was heated stepwise from 160°C to 210°C at a rate of 5°C per minute on a hot plate under an inert atmosphere.
and keep at the same temperature of 210℃ for 60 minutes, at 1 minute per minute.
Heating from 210℃ to 400℃ at a rate of 0℃, and finally 2
It was cured by keeping at the same temperature of 400° C. for 40 minutes. SEM examination of the above sample J showed complete filling and excellent substrate flatness.

Example 7 Mizoko Jf1 Method - A 60 to 70 weight fl:% solution of aromatic acetylene oligomer (PEPE) dissolved in a suitable solvent was formed. The solution was filtered through a 05μ Fluoropore filter and then deposited onto a Noricon wafer containing grooves. The above wafer was heated at 6000 to 110000 r.
Rotate for 40 to 60 seconds at 100 ml and place on a hot plate at 80° C. under nitrogen.

The hot plate was heated at a rate of 10°C per minute to the selected curing temperature. After the curing temperature was maintained for a sufficient period of time (30 minutes to 4 hours) until sufficient curing occurred, the hot plate was cooled to room temperature and the wafer was removed. As a result of the above method, PE of 1 to 10μ
From the coating of PE, sea urchins were obtained with excellent surface flatness, without any unfilled grooves.

Example 8 1. A wafer with grooves was dissolved in xylene.
It was coated with 5% by weight PEPE (0.45μ filtered) and spun at 3000 rpm to form a 2.8μ thick coating. 2 The above PEPE coated wafer was placed on a 50°C hot-plate and the hot plate was heated to 400°C at a rate of 99°C per minute and maintained at 400°C for 30 minutes. 3. The above wafer was etched to the final position +10%. The above etching was performed using an RIE device at a flow rate of 2.10 sec.
This was done using 0 watts of R4 and a pressure of 85-9 QmTorr. 4 Immerse the wafer in HF,
Washed and dried before recoating. After the above cleaning, the wafers can be dried by dipping in isopropanol, spinning dry, and then baking at 100° C. for 15 minutes J5. The sea urchins were recoated with 65% by weight PEPE (filtered to 0.45μ) dissolved in Ki/Lene and spun at 3000 rpm. 6. P above
The EPE coated wafer was placed on a 50°C hot plate and the hot plate was heated to 400°C at a rate of 99°C per minute and maintained at 400°C for 60 minutes. 7
The above sea urchin... is etched again to the final position. 8
The above PEPE coated wafer was heated to 50°C.
It was placed on a plate and heated to 425°C at a rate of 99°C per minute and maintained at 425°C for 60 minutes. 9. Examination by SEM showed well-filled grooves and excellent surface flatness.

c.

Claims (1)

[Claims] In a method for filling deep dielectric isolation trenches in a semiconductor device, an aromatic polymer oligomer having a reactive ethynyl group is dissolved in a solvent, and 2 to 2,000 cs. forming a solution having a viscosity, filtering the solution, coating a semiconductor device including the groove with the solution to form a coating, evaporating the solvent, and heating and curing the coating. , Method of filling trenches for dielectric isolation.